pH Up & Down Calculator
How much pH Up or pH Down your pool needs to reach the ideal range — the calculator picks the direction based on your current reading.
Add about
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Estimate only — always follow the dosing instructions on the product packaging and never mix chemicals.
Track it automatically with Algae Later →What should pool pH be?
Keep pH between 7.2 and 7.6 (target 7.4). Too high and chlorine stops working and scale forms; too low and the water turns corrosive and stings. If your reading is above 7.6 you add pH Down; below 7.2 you add pH Up.
Frequently asked
- pH Up vs pH Down — which do I need?
- Above the 7.2–7.6 range, add pH Down (sodium bisulfate / acid). Below it, add pH Up (soda ash). Enter your current pH above and the calculator tells you which and how much.
- Why does my pH keep drifting up?
- New plaster, aeration (fountains, jets) and some chlorine types push pH up over time. That's why regular testing every 2–3 days matters.
- Should I fix pH or chlorine first?
- Balance pH first — chlorine is far more effective when pH is in range, so correcting pH makes your chlorine go further.